Multi-Functional Heat Pulse Probe for the Simultaneous Measurement of Soil Water Content, Solute Concentration, and Heat Transport Parameters

Abstract

scales, it is important that the various coupled transport processes are measured simultaneously.Water, solute, and heat transport processes in soils are mutually In addition to being variable in time, soil transport interdependent as each includes convective water flow and each transproperties and processes are known to be highly variable port mechanism is partly controlled by fluid saturation, pore geometry, in space. Because of the inherent soil spatial heterogenetemperature, and other soil environmental conditions. Therefore, their measurement in approximately identical measurement locations and ity, the outcome of a soil measurement is dependent on volume is essential for understanding transport phenomena in soils. measurement volume. The scale dependency of soil prop-We introduce a 2.7-cm-diameter multi-functional heat pulse probe erties and their relation to vadose zone flow and trans-(MFHPP), which consists of a single central heater, four thermistors, port processes have precluded a unifying concept of and four electrodes (Wenner array) that together are incorporated in water flow and chemical transport across spatial scales, six 1.27-mm-o.d. stainless-steel tubes. The bulk soil thermal properties from the microscopic pore scale to the macroscopic local and volumetric water content of Tottori Dune sand were determined scale (Hopmans et al., 2002b). Therefore, it is essential from the measurement of the temperature response of all four thermisto estimate soil properties at the same location, using tor sensors after application of an 8-s heat pulse by the heater sensor. approximately equal measurement volumes. Hence, the Simultaneously with the temperature measurements, the bulk soil justification of the proposed MFHPP is to ensure that electrical conductivity (EC b ) was measured using the Wenner array, from which soil solution concentration (EC w ) can be obtained after the different measurement types are conducted within calibration. All measurements were taken during multistep outflow identical soil volumes, minimizing soil heterogeneity efexperiments, which also allowed estimation of the soil's hydraulic fects and providing more accurate measurements of soil properties. We demonstrated that the MFHPP can effectively measure physical properties for environmental monitoring. volumetric water content, thermal properties, and EC b , and can be The proposed MFHPP originates from the dual-probe used to indirectly estimate soil water fluxes at rates larger than 0.7 heat-pulse (DPHP) method introduced by Campbell et m d Ϫ1 in the sand.

Measuring Solid Percentage of Oil Sands Mature Fine Tailings Using the Dual Probe Heat Pulse Method

“…This corresponded to thermal diffusivity values between 2.09 × 10 −7 and 3.96 × 10 −7 m 2 s ‐1 . The values of thermal properties were in reasonable ranges compared with other reports (Noborio et al, 1996; Bristow, 1998; Mori et al, 2003). The water content of the MFT samples decreased with increasing depth (Table 2).…”

“…The ends of the heating wire and the thermistor of the probe were soldered to 18 AWG electrical wires and connected to a datalogger. More detailed information on probe construction and setup can be found in Mori et al (2003) and Liu and Si (2010). A datalogger (Model CR10X, Campbell Scientific) and multiplexers (Model AM16/32, Campbell Scientific) were used to control the heat pulse, to monitor the electric current through the heater, and to measure the temperatures as a function of time.…”

Measurement of the physical properties of the snowpack

“…The heater needle warms up, and a rise in temperature is sensed by a thermocouple. The thermocouple is placed either inside of the heater needle (single needle) or inside another needle situated at a radial distance to the heater needle (multiple needle) [ Mori et al , ]. The change in temperature during heating or cooling of the needle is related to material properties by a mathematical model [ Kluitenberg et al , , ; Carslaw and Jaeger , ; Liu and Si , , ; Mori et al , ].…”

Dependence of the Electrical Conductivity on Saturation in Real Porous Media

“…Comparison of predicted with measured electrical conductivity (σ) in soils presented by Mori et al (2003, labeled MHMK2003) and Tuli and Hopmans (2004, labeled TH2004) at different bulk solution (σ b ) values.…”